1. Technical Field of the Invention
This invention concerns a pouring closure for combipacks as well as containers sealed with foil material of all types, which includes a piercing edge arrangement. Moreover, liquid packings in the form of such combipacks out of foil-laminated paper are particularly considered, in which for example milk, fruit drinks, variety of drinks or general liquids, even out of non-food range, are packed. But the closure can be used also for combipacks, in which bulk materials like for example sugar, semolina, rice or a variety of chemicals and similar materials are kept or packed. In case of paper, it is a question of a laminated material, perhaps a paper or cardboard web coated with plastic, like for example polyethylene, and/or aluminium. Usual volumes of such packings extend from 20 cl up to 2 liters and more. Alternatively, the pouring closure can also be assembled on containers, which are sealed by a foil material, for example on a variety of bottles out of glass or plastic or on similar containers.
2. Description of the Prior Art
Such closures out of plastic are available in different embodiments. They form, if they are determined for a combipack, essentially a pouring edge or pouring nozzle with a shoulder projecting radially out from its bottom edge, which forms a closing flange at this edge or nozzle. In case of a nozzle, this is mostly equipped with an external thread, on which a threaded cap can be screwed as closure. In case of a bottle closure, the nozzle can be fixed or screwed on a bottle mouth. Other pouring closures have a lid which is hinged via an internal hinge that can be opened. Such a pouring closure is flanged on the combipack, in which it is welded leak-proof on the combipack with the bottom side of its projecting edge, that is with the bottom side of its flange. The free passage at the bottom end of the edge or nozzle is thereafter sealed by the paper and the membrane liner of the combipack.
The foil-reinforced paper going through below the cut-open nozzle or pouring closure or the foil membrane running below the nozzle or closure must be cut, torn open or pressed out for opening, so that the passage is made free and the liquid or the bulk material can be poured out or emptied out from the container through the nozzle or the pouring closure. In addition to this, a sleeve is arranged within the nozzle, which is carried along by the threaded cap during its turning and therefore is turned in the same rotating direction by it. This moves downwards steadily with the screwing out through a thread on the inner side of the nozzle and the outer side of the sleeve running counter to the thread on the outer side of the nozzle and the inner side of the cap, that is if this is moved upwards against the fluid packing. The lower edge of the sleeve is provided with one or more tearing or cutting teeth. The sleeve shall press out or cut out a disc from the foil-reinforced paper or the foil membrane running through below it as a result of its rotating and steady downward motion.
Usually, however, such self-opening closures do not always function fully satisfactorily. The discs are not cut out clean from the paper foil or the foil membrane, but on the contrary these sleeves simply press out a piece of foil from it. The remaining edge is frayed out and consequently projects paper or foil shreds into the passage, which should be removed properly. These shreds project often even below in the container and possibly block the path for the air to be taken in into the container from outside during the pouring or emptying out or they project fully in the way of the stream flowing out or the materials being emptied out. In case of large packings with strong foil-reinforced paper or cardboard, the opening is carried out even less reliably and cleanly. The sleeve moving downward slowly and rotating simultaneously touches the foil-reinforced web to be cut with its entire bottom edge and completely presses it towards the bottom and rotates on it until a hole is scraped through or broken through and then cut. A problem as to why the cutting is messy lies among others in the fact that the foil to be cut yields to the pressure of the sleeve, working to a certain extent as boring head, somewhat downwards and consequently the sleeve no longer acts on a plane of paper foil but on foil bulged downwards. Further, the solutions until now require a suitable force from the side of the user because of the form of the sleeves, which are designated analogously also as punch, since they break through simply one more paper-foil piece in order to cut out a circular disc cleanly. That is, a large torque must be applied since the teeth or the ripper on the lower punch edge or sleeve edge have to at first scratch the foil distributed around the entire circumference clean and afterwards overcome a large rotational resistance. They act in the top-most layer of the paper thickness similar to tearing teeth, that is, scraping, pressing and tearing, instead of acting as real cutting blades with sharp cutting edges.
In order to simplify the breaking out or tearing out, the foil material or the composite material is pre-weakened by means of lasers or punches at the desired perforation locations for the usual self-opening closures of this type. Technically this pre-weakening is rather expensive. One requires costly equipment and the handling for the processing of the perforation locations on the films is time-consuming. In spite of these expensive weakening measures, the usual self-opening closures do not cut clean, but tear the paper or plastic foil before they cut the same clean, which explains the large rotary resistances. Due to the large rotary resistances, even breakages of the transmission media occur now and then, which should take over the transfer of the torque from the threaded cap to the punching sleeve, or the carrier cams that are provided, which engage in the grooves of the punching sleeve, jump out from these grooves. If such a thing happens, the self-opening closure is not capable of functioning any more.
A further problem is that the torn out foil disc or the foil disc cut out halfway by the punching sleeve is tilted downwards too less or the foil disc remains tilted downwards with too little strength over the usage duration, since the punching sleeve is not fixed securely in the end position. All these problems should be solved by a correct self-opening closure.
The solutions known till now are moreover of relatively large size. In the case of a nozzle, this must accommodate a punching sleeve, which must be moved down by some millimeters in order to open the composite laminate, irrespective of whether the sleeve is turned further additionally or not. The transmission medium for the pressing downwards and, if necessary, for the rotating of the sleeve requires lot of space and corresponding size, which is however unfavourable for the stackability of the combipacks equipped with it. Moreover, the individual components are complicated in their design. They are produced separately, namely as nozzles, as screwable cover and as punching sleeve, adjustable in the nozzle. These three parts have to be assembled after the injection molding, which is expensive and, for large quantities, which is the case here, requires particularly cleverly devised and costly automatic assembly machines.